City calls for reservoirs survey

NEWPORT — The city is proposing to conduct a survey of St. Mary's and Sisson ponds in Portsmouth, which are among the nine reservoirs owned by Newport Water.

"We have maintenance work to do on the dams and properties surrounding the reservoirs," said Julia Forgue, the city's director of utilities. "We need a clean document of where the property lines are. Right now, we don't have good survey boundaries. A lot of the records are old."

The first Lawton Valley treatment plant and the Lawton Valley Reservoir were built in 1942, and connected to St. Mary’s and Sisson ponds by pipes about that time.

The utilities department is proposing to hire Able Engineering of Little Compton, the lowest-qualified bidder, to do the work under a $49,500 contract. The City Council plans to take up the contract on Wednesday.

The two ponds cover about 249 acres, which includes 185 acres of water and 64 acres of land. Besides the boundaries, the firm would conduct topographic surveys of all reservoir access roads, the ponds' dams, the Sisson Pond causeway and the St. Mary spillway connection to Sisson Pond. The firm also is being asked to set granite boundary markers.

"Upkeep and maintenance of source water reservoirs is a critical element in providing safe drinking water," wrote Robert Schultz Jr., deputy director of utilities, in a memorandum to council members.

"Recent inspections identified areas of concern," he wrote. "The detailed survey of St. Mary's and Sisson ponds is the next step in evaluating these reservoirs."

The state Office of Compliance & Inspections, a division of the Rhode Island Department of Environmental Management, determined in 2016 that vegetation on the dam embankments at the reservoir dams, as well as within the primary and auxiliary spillways, did not allow a proper examination by a state DEM inspector. Other maintenance measures were addressed as well in the report at that time.

The city has been addressing those concerns, but now that the two water treatment plants have been either newly built or totally upgraded, there is more time and resources to focus on the reservoirs, Forgue said.

Newport Water opened up its new treatment plant at Lawton Valley in September 2014. Construction began in August 2012. That year, state-of-the-art treatment processes also were introduced at a revamped Station 1 water treatment plant on Bliss Mine Road in Newport.

The raw water coming to the plants have a high level of organics and impurities because the nine reservoirs on Aquidneck Island and in Tiverton and Little Compton are generally in highly developed areas and are relatively shallow, Forgue said. That presents maintenance challenges at all the nine reservoirs owned by the Newport Water, besides maintaining water treatment processes.

In 1876, North Easton’s Pond on the Newport-Middletown line became the first reservoir developed for the city’s water system. South Easton’s Pond in Newport, Nelson and Gardiner ponds in Middletown, and St. Mary’s and Sisson ponds in Portsmouth were added to the system by 1900. Water from St. Mary's Pond flows into Bailey's Brook, which feeds the Easton’s ponds.

The Station 1 water treatment plant on Bliss Mine Road was built in 1909-10. In the early 1940s, during World War II, there were increased military and civilian needs for water. Nonquit Pond in Tiverton was acquired at about that time and connected with a pipeline across the Sakonnet River to St. Mary's Pond.

The Harold E. Watson Reservoir in Little Compton was acquired in 1960 and connected to St. Mary's reservoir through the Nonquit Pond pump station.

It is a challenge for Newport Water to reduce the phosphorus and other impurities going into the reservoirs, Forgue said. By improving raw water quality through maintenance and other measures, the less the department has to spend on treatment.

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